Improving metallicity estimates for very metal-poor stars in the Gaia DR3 GSP-Spec catalog

Understand

The Gaia DR3 GSP-Spec parameters, including metallicity, for VMP stars suffer from parameter degeneracy due to a lack of information in their spectra.

• Furthermore, the recommended quality cuts filter out the majority of the VMP stars because some of them are confused with hot stars or cool K and M-type giants.
• We aim to provide more precise metallicity estimates for VMP stars analysed by the GSP-Spec module by taking photometric information into account in the analysis.
• We reanalyzed FGK type stars in the GSP-Spec catalog by computing the Ca triplet equivalent widths from the published set of GSP-Spec stellar parameters.